Method of making portland cement.



J. M. GARRERE. METHOD OF MAKING PORTLAND CEMENT.

APPLICATION FILED NOV. 24, 1908.

Pat nted Dec. 20, 1910.

U PATENT OFFICE,

.s'rAINLEss CEMENT on NEW JERSEY.

" 'To fal liihom 'itjmay concern:-

'Be. 1t "know n that I, JOSEPH LIAXWELL lAnnEnE',-a cltlzen of the United States, resid ng .at Allentown, county of Lehigh,

State of Pennsylvania, have invented certain new? and usefulImprovements in Methods of Making Portland Cement, of which the scri tion.

following is a full, clear, and' exact del\" y invention relates to aprocess of making Portland cement, and has for its object to produce a more reliable process resulting inan improved product, to reduce the cost, and to provide a process of makmg such cement from a mix containing clay IlCh 1n alkalies';

ytegrates, and. .on leaving the .:rotary'.. If

In-the lnan'ufacture of Portland cement, it "has heretofore been the accepted practice to avoid what are known as alkaline clays, that is, clays rich in or containing an excess alkalies, such as'clays containing more tiian 2% or 3% of alkalies,'as such excess has heretofore been liable to interfere with the burning and result in the production of a readily disintegrating cement. \Vhenaclay is rich in alkali, or alkali 1s added to the -mix', and the raw mix is burn d in an ordinary rotary kiln with the pr vailing process, either coal or oil, the fluxirg is liable to begintoo quickly, (3., before all of the carbonic acid gas is driven off from the limestone, and the alkali combining with the silica forms a glass which in rolling around the rotary gathers unburned material, fluxing on the surface as it rolls around and forming a-ball or lar e clinker, which is subjected for a long period to clinkering heat and contains within it much unburned materiah This action is due to the .too quick fusing of the, silica and alkall, as above stated, and consequent formation of an outer coating or shell; which prevents the flame or heat of the rotary from acting when it does not choke the discharge end I of the. rotary, breaks to pieces and disinfalls to 7; powder *immedlately v the heat in the rotaryis raised to such ia point under these conditions as to penetrate the ball or mass thus formed, it will not only fuse the mass,

but will melt it, causing it to flow and ad- JOSEPH MAXWELL oAmtEnE, 0F- ALLENTOWN, BENNSYLVANIA, ASSIGNOR 'ro BLANQ" coMrANY, or LLENrowN, PENNSYLVANIA; A CORPORATION ,M rHon'or MAKING PORTLAND c M N'r'.

here to the kiln'and also causing the format- Specification of Letters Patent. Patented 3 1910, v Application med November 24, 1908. Serial No. 464,243. i i i tion of undesirable chemical combinations in the cement, which will make it unsound.

- 'By my invention I am able to use a mix rich in'alkali and to avoid the difliculties and disadvantages referred to above, roducm a uniform and improved pro not,

and aso reducing the cost of burning ce-- I ment.

The following is description of 'my in-' vention, reference being had tothe ac'com-.

panyingfldrawings, which show a kiln for burning the cement.

Figure 1 shows a; lmgtudinalsection of i the kllIl. Flg. 2 is an on view of the hood. A

, Fig. 3 is a section on the line us -w of Fig. 1.

Referring-more particularly to. the draw-. mgs, A isthe rotary, B is the stack, C is the charging chute, D is'the hood having the discharge orifice D, E is an oil burner having an oil supply pipe F, and a compressedair supply pipe Gr.

H is a fan-for introducing the desired-w amount of air at low pressure at H Means for throttling all three of the passo The rotary is mounted upon the rollers sages are provided at F, G and H.

I I and J-J, and revolved by power sup-i phed to gears J from any convenient source and is provided with a fire brick lining K.

L is a chute leading from the discharge opening D. i N is the usual peep hole.

A second burner "E may also be used to increase the flame, the low pressure alr nozzle being between the second bprner and the material.

In carrying out my process, I feed the mix, consisting of limestone and an alkaline= clay, into the rotary at theupper end, heat the rotary near the discharge end to a clinkering heat and pass the products of combustion through the rotary so as to keep the temperature'in the upper part of my ro tary below the sinterin point of the silica in the presence of alka ice, but hot enough to drive off the moisture and carbonic acid" gas before the mix reaches the sintering zone, bringing my mix by the revolutions of the rotary graduallycloser to the flame'O."

I so regulate the temperature in the rotary that the moisture and carbonic acid gas are f first drivenout completely and the mass is then, and nottill substantiallythen, sub- I jected to the nuxmg heat of the flame until clinkered, and substantially immediately thereafter discharged. To accomplish this purpose, I use an intense short singeing flame, producing a clinkering of the material rolling or passing by it, and discharge the clinker as soon as formed. Any fuel can be used, but preferably fuel as free as possible of ash, phosphorus or sulfur, and I have found that I obtain the best results and can control the fusion zone to better advantage by using both compressed and low pressure air with the fuel. I preferably use crude oil, atomizing it by a small volume of compressed air or steam, an supply from an ordinary fan a large volume of air at. low pressure under the axis of my kiln. This enables me to supply the necessary air to form perfect combustion with the oil uniformly and at all times, and I use, as stated above, the compressed air or steam simply to atomize the oil. The axis of the flame O is preferably substantially parallel to the axis of the cylinder. so as to sings but not impinge upon the material. and the flame is the direct product of immediate and perfect combustion on leaving the nozzle or burner.

The mixture composed of clay rich in alkali and of limestone is fed into the upper end of the rotary in the ordinary manner, the proportions being preferably 24% of alkaline clay to 76% of limestone. For white cement these materials should be substantially free from iron. As the materials pass through the rotary, the heat first drives off the Carbonic acid gas and a portion of the alkali, together with any moisture which may be present. Practically all of the carbonic acid gas is driven off before the mixture reaches the fusing zone, and all. the, elements, lime, silica alumina and the remaining alkalies, I are heated gradually to the point of fusion, sothat the chemical combination takes place simultaneously and produces a perfect clinker of Portland cement. 'hen the material is within the fusing zone, the fusion and clinkering take place at a comparatively low degree of heat on account of the presence of the remaining alkali and the fact that the materials have been graduv ally heated to the point of chennc1l combination.

As the rotary revolves, it carries the raw mix and partly singed material with it, causing it to travel toward the discharge end, and at. the same time carries it to a height on its inner circumference dependent on the speed and feed, and then drops it in a continuous stream to the lower inner circumference of the rotary, and whence is again carried up and dropped. In dropping, it forms a curve and a slide similar to the breakers of the ocean on the shore.

The flame should be directed in its course along this curve and made to singe the main body near the discharge end, as it is carried up by the rotary and dropped by it, so that once the material has reached the fusing zone 'it will feelits full effect continuously and uninterruptedly until it is discharged in a perfect clinker. To accomplish this, I have found it best to place the burner .E to the side of the center of the rotary on which the material is carried by and slightly under the horizontal line. The exact distance must be determined by the diameter of the rotary and size of the linin I preferably also place a second burner E on a line with the center of the rotary and in the o posite direction about, the same distance. 1 0 produee a short flame I use ateach burner a small volume of com ressed air or steam to atomize the oil or uel, and low pressure air from a 'fan or similar apparatusrto cause perfect combustion. I The amount of low pressure air shouldbe so regulated that perfeet combustion takes place at ,once and within a short distance from the discharge end of the rotary, and the flame should not exceed 25% of the length of the kiln. The

(OI'HPIBSSEd air or steam should only be used to perfectly atomize the fuel and perfect combustion should be created by low pressure air. To perfectly control the singeine effect of-tli-e flame, I have the low pressure nozzle placed substantially under the center of the rotary and lower than the burner. \Vhen two burners are used, it is located between them as shown. I thereby obtain not only a perfect mingling of the air with the atomized fuel, but keep the flame singeing on at least two-thirds of the circumference of the kiln where the material to be clinkered is continuously being carried and tumbled about.

If the mixture wereburned with the ordinary long flame, only aportion of the can bonic acid gas and very little of the alkali would be driven off before sintering would begin. P 'actically all the alkali would com bine with the silica, forming a large mass of glass which would contain a large amount of unburned material.

lVith the'ordinary proce s in a rotary of the usual length. sixty feet. whether burning oil or coal. the tlzune'itsclf traverses practically or very nearly the entire length of the rotary. and the :-l'2ltl\1 temperature is rarely under 1.000 I. or 1200 I. when the kiln is doing its duty. llnder my process the clinkering' flame O is a short flame extending over preferably only 15 or 20? of th e length of the rotary. The intense heat is. therefore to be found. in Lhisfirst 20% distance. The economyqand Saving is very great. as my stack temperatures are reduced under all circumstances and need never show over 700 F. when a mix rich in 'alkalies is treated, but the main advantage of my invention is that the entire process is more 'lllllfOllll, sure and. erfect, 'beiiigtlile lO tllB fact that the materials are raised gradually to a fusing heat so that they are thoroughly burned and then clinkered and substantially ,If an ordinary mix, '5. e., a' nnxnot rich in-i-alkali, werextreated by my process, the a1 6 Would be so .cofm-pletely eliminated prior" I to -its "reaching the fusingzone that it would not be clinkered, properly unless a, degree of heat'vwere used-higher than that required for the alkaline clay mix since the cli'nkering would require even'a" higher degree of heat 'than isrnmy used in the ordinary process. "process With-ahigher degree of heat is ht ver useful with such mixes on account of t-liegi'adual heating and early driving on w t substantially all the carbon c? acid ga ev re ilting'in a thorough burning and the elimination ofv danger of overburning. 1 a

lVhat I claim is: .1. In the manfac-ture of Portland cement,

athe improvement which consists in subject- ,iii g'fltma relatively low and gradually in creasing heat a unit compris ng limestone and ClflY Il'Qll 1n alkalies, 'clrlvmg ofi'"sub- ..stantiallyfal'l the carbonic acid gas and a portion of the alkalies, thereafter subjecting the-mix to ahigher and cllnkering heat prodncedby a short intense singeing flame and tfgs charging the-resulting clinker substantially as soon as. formed, the gradual l1eating being due'to the passage of products of combustion of the short flame through the upper part of the'kiln.

2. 'In'the manufacture of Portland cement, the improvement AVlllCh consists in passlng a mix through a rotary, heating the rotary by burning near its discharge end in the presence of a current of an fron 'a 10W resjsure source fuel; tomized by a small vo ume thereby a-shoitintense singeing flame, ass

ing the resulting clinker substantially as soonfas formed. a r

3; In the manufacture of Portland cement, the improvement which consists in introducuine of fluid under high 11365511115 andover vlying the current, of an mm the low pres, sure souree, producing-thereby a short in--' tense singeing flame, passing the products of combustion. throughthe kiln in one direc. tion, and passing the mix through the kiln the resultinglclinker substantially as soon as formed.

4. In the manufacture of Portland cement, the improvement which consists in forming a mix containing approximately 7 6 per cent. of'liniesto11e and 24-per 'cent.,of natural alkaline clay, the clay containing about three 'per cent, of alkali, the mix being substantially free from iron. subjecting'l said mix to a relatively low and gradually increasing heat, driving on substantially all the carbonic acid gas and a portion of the alkalies, thereafter subjecting the mix to a short intense singeing flame and discharging the resulting clinker substantially as soon as formed, the gradual heatin being due'to singeing flame.

IMAXWELL CARRERE.

Vitnesses: I Q

- 4 H. B. BROWNING,

M. E. GARRETT.

of fluid under high pressure'and nroducing ing theprodu cts of oon'ibustion throng the, rotary in a direction opposite to the 1ongi-' tudlnal-movement of the mix; and dischaigin the opposite direction and discharging the products of combustion of the short' ing'into the kiln near its discharge end a current d'f air from a: lowpressure source, and a current of fuel atomizedby a small vol-. 

